CVE-2021-47123 (GCVE-0-2021-47123)

Vulnerability from cvelistv5 – Published: 2024-03-15 20:14 – Updated: 2026-05-11 13:48
VLAI
Title
io_uring: fix ltout double free on completion race
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring: fix ltout double free on completion race Always remove linked timeout on io_link_timeout_fn() from the master request link list, otherwise we may get use-after-free when first io_link_timeout_fn() puts linked timeout in the fail path, and then will be found and put on master's free.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 90cd7e424969d29aff653333b4dcb4e2e199d791 , < 1f64f5e903b9d1d157875721e02adadc9d6f0a5d (git)
Affected: 90cd7e424969d29aff653333b4dcb4e2e199d791 , < 447c19f3b5074409c794b350b10306e1da1ef4ba (git)
Create a notification for this product.
Linux Linux Affected: 5.11
Unaffected: 0 , < 5.11 (semver)
Unaffected: 5.12.10 , ≤ 5.12.* (semver)
Unaffected: 5.13 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:24:39.841Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/1f64f5e903b9d1d157875721e02adadc9d6f0a5d"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/447c19f3b5074409c794b350b10306e1da1ef4ba"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-47123",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-09-10T15:55:29.439890Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-09-11T17:33:24.138Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/io_uring.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "1f64f5e903b9d1d157875721e02adadc9d6f0a5d",
              "status": "affected",
              "version": "90cd7e424969d29aff653333b4dcb4e2e199d791",
              "versionType": "git"
            },
            {
              "lessThan": "447c19f3b5074409c794b350b10306e1da1ef4ba",
              "status": "affected",
              "version": "90cd7e424969d29aff653333b4dcb4e2e199d791",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/io_uring.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.11"
            },
            {
              "lessThan": "5.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.12.*",
              "status": "unaffected",
              "version": "5.12.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.12.10",
                  "versionStartIncluding": "5.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.13",
                  "versionStartIncluding": "5.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: fix ltout double free on completion race\n\nAlways remove linked timeout on io_link_timeout_fn() from the master\nrequest link list, otherwise we may get use-after-free when first\nio_link_timeout_fn() puts linked timeout in the fail path, and then\nwill be found and put on master\u0027s free."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T13:48:29.602Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/1f64f5e903b9d1d157875721e02adadc9d6f0a5d"
        },
        {
          "url": "https://git.kernel.org/stable/c/447c19f3b5074409c794b350b10306e1da1ef4ba"
        }
      ],
      "title": "io_uring: fix ltout double free on completion race",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47123",
    "datePublished": "2024-03-15T20:14:28.888Z",
    "dateReserved": "2024-03-04T18:12:48.839Z",
    "dateUpdated": "2026-05-11T13:48:29.602Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-47123",
      "date": "2026-05-25",
      "epss": "0.00018",
      "percentile": "0.04818"
    },
    "fkie_nvd": {
      "descriptions": "[{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nio_uring: fix ltout double free on completion race\\n\\nAlways remove linked timeout on io_link_timeout_fn() from the master\\nrequest link list, otherwise we may get use-after-free when first\\nio_link_timeout_fn() puts linked timeout in the fail path, and then\\nwill be found and put on master\u0027s free.\"}, {\"lang\": \"es\", \"value\": \"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: io_uring: corrige la doble liberaci\\u00f3n de ltout al finalizar la ejecuci\\u00f3n. Elimina siempre el tiempo de espera vinculado en io_link_timeout_fn() de la lista de v\\u00ednculos de solicitud maestra; de lo contrario, es posible que obtengamos use-after-free la primera vez que io_link_timeout_fn() coloca el tiempo de espera vinculado en la ruta de falla, y luego ser\\u00e1 encontrado y puesto en master gratis.\"}]",
      "id": "CVE-2021-47123",
      "lastModified": "2024-11-21T06:35:26.560",
      "published": "2024-03-15T21:15:07.217",
      "references": "[{\"url\": \"https://git.kernel.org/stable/c/1f64f5e903b9d1d157875721e02adadc9d6f0a5d\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/447c19f3b5074409c794b350b10306e1da1ef4ba\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/1f64f5e903b9d1d157875721e02adadc9d6f0a5d\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/447c19f3b5074409c794b350b10306e1da1ef4ba\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}]",
      "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "vulnStatus": "Undergoing Analysis"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-47123\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-03-15T21:15:07.217\",\"lastModified\":\"2025-01-14T15:02:28.120\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nio_uring: fix ltout double free on completion race\\n\\nAlways remove linked timeout on io_link_timeout_fn() from the master\\nrequest link list, otherwise we may get use-after-free when first\\nio_link_timeout_fn() puts linked timeout in the fail path, and then\\nwill be found and put on master\u0027s free.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: io_uring: corrige la doble liberaci\u00f3n de ltout al finalizar la ejecuci\u00f3n. Elimina siempre el tiempo de espera vinculado en io_link_timeout_fn() de la lista de v\u00ednculos de solicitud maestra; de lo contrario, es posible que obtengamos use-after-free la primera vez que io_link_timeout_fn() coloca el tiempo de espera vinculado en la ruta de falla, y luego ser\u00e1 encontrado y puesto en master gratis.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-415\"},{\"lang\":\"en\",\"value\":\"CWE-416\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.11\",\"versionEndExcluding\":\"5.12.10\",\"matchCriteriaId\":\"27384800-AB48-4C08-891E-34B66F5FC4AA\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/1f64f5e903b9d1d157875721e02adadc9d6f0a5d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/447c19f3b5074409c794b350b10306e1da1ef4ba\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/1f64f5e903b9d1d157875721e02adadc9d6f0a5d\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/447c19f3b5074409c794b350b10306e1da1ef4ba\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://git.kernel.org/stable/c/1f64f5e903b9d1d157875721e02adadc9d6f0a5d\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/447c19f3b5074409c794b350b10306e1da1ef4ba\", \"tags\": [\"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-04T05:24:39.841Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-47123\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-09-10T15:55:29.439890Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-09-11T12:42:16.514Z\"}}], \"cna\": {\"title\": \"io_uring: fix ltout double free on completion race\", \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"90cd7e424969d29aff653333b4dcb4e2e199d791\", \"lessThan\": \"1f64f5e903b9d1d157875721e02adadc9d6f0a5d\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"90cd7e424969d29aff653333b4dcb4e2e199d791\", \"lessThan\": \"447c19f3b5074409c794b350b10306e1da1ef4ba\", \"versionType\": \"git\"}], \"programFiles\": [\"fs/io_uring.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.11\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.11\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.12.10\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.12.*\"}, {\"status\": \"unaffected\", \"version\": \"5.13\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"fs/io_uring.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/1f64f5e903b9d1d157875721e02adadc9d6f0a5d\"}, {\"url\": \"https://git.kernel.org/stable/c/447c19f3b5074409c794b350b10306e1da1ef4ba\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nio_uring: fix ltout double free on completion race\\n\\nAlways remove linked timeout on io_link_timeout_fn() from the master\\nrequest link list, otherwise we may get use-after-free when first\\nio_link_timeout_fn() puts linked timeout in the fail path, and then\\nwill be found and put on master\u0027s free.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.12.10\", \"versionStartIncluding\": \"5.11\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.13\", \"versionStartIncluding\": \"5.11\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2025-05-04T07:04:35.817Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-47123\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2025-05-04T07:04:35.817Z\", \"dateReserved\": \"2024-03-04T18:12:48.839Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-03-15T20:14:28.888Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.